Context Navigation

3. Execute Experiment

With any changes to port numbers and MAC addresses in the switching and startup scripts, save the scripts, and execute /root/StartupScripts/gec20_setup.sh. This might seem redundant, since we have already run this script, but the intention is to show you how it will remove your OVS network for you and kill any Floodlight controllers without you having to explicitly do so. Executing this script again will also apply any and all changes made to the setup script and the switching script set as the initial flow script.

Open another SSH connection to the client node in Orbit and start a ping to the IP address of the server node. The ping should succeed and should be over Wifi -- the default initial interface.

$ ping 10.41.4.1

Run the WiMAX switching script, /root/SwitchingScripts/gec20_switch_to_wimax.sh. This script will remove all flows on all OVS instances and will insert static flows directing all packets out the WiMAX interface and in from the WiMAX interface to the tap interface.

4. Analyze Experiment

Congratulations! You have just completed a vertical handoff! So, do you want proof the handoff actually took place? If you do not notice a difference in the ping times, you can view the packet counts on each OVS bridge on a per-flow basis.

For each flow there is a packet count of the packets that have matched and then were handled by the flow's actions. If you switch to WiMAX, you will notice the packet count increase for the WiMAX flows on the br_wimax OVS bridge, while no packets are matched on the WiFi interface (since there are no flows at all). The opposite is true if you switch to WiFi. These flows are what control the "flow" of packets to and from the application and the physical interface of choice. Because we have disabled Forwarding in Floodlight, only the flows we explicitly insert ourselves will be present in the OVS bridges. Thus, the packet counts on these flows are the only packets being switched in our virtual network.